Composite plastic parts are of great value in industry because of their high strength and light weight. Tubular, simple, and complex structures are produced by laying on, wrapping, or coating a core mold, form, or mandrel, with the composite plastic and curing the composite at appropriately high temperature.
For some configurations, the composite material must be pressed into areas of the form or mold which is accomplished by placing the form or mold with overlaying composite material into an enclosing bag, followed by vacuum evacuation of the bag so that the outside pressure against the bag forces consolidation of the composite material and conformation with the form or mold shape. Failure to get sufficient consolidation and conformation of the composite into depressed areas of the form or mold results in unacceptable defect in the product.
Bag/breather elongation and bridging deficiencies account for the majority of defect issues in composite curing and is normally due to the fact that the outside consolidation force is not able to make intimate contact with the composite material that is to be consolidated. The insufficient force for compressing (consolidating) composite material in problem areas is mitigated by applying the expandable medium of the present invention to the problem areas so that sufficient pressure is applied during consolidation and curing.